Method and apparatus for relieving the loading of a service function node in a telecommunications signalling network

Abstract

In order to relieve the loading of a service control point SCP in a telecommunications signalling network, query messages addressed to the SCP are intercepted prior to receipt by the SCP. These intercepted query messages are examined and response data generated, at least for certain query types. For a query message for which response data is generated, the query message is replaced by a response message addressed to the querying entity. The response message is then forwarded on in the same sense as the received query message. In a preferred implementation, the forwarded response message will next be received by a signalling transfer point STP and be directed back to the querying entity.

We claim: 
     
       1. A method of relieving the loading of a service function node to which query messages are addressed over a telecommunications signalling network from a querying entity, said query messages each including source and destination data and giving rise to corresponding response messages returned to said querying entity over said signalling network; said method comprising the steps of: (a) intercepting messages on at least one link of said signalling network and selecting from the intercepted messages at least certain of said query messages addressed to the service function node;   (b) for each selected query message, generating appropriate response data;   (c) replacing each said selected query message with a response message including said response data, the response message having its destination data set to the source data of the corresponding query message; and   (d) forwarding on over the signalling network the response messages provided in step (c), said response messages being forwarded in a direction corresponding to that in which said query messages were traveling when intercepted in step (a).   
     
     
       2. A method according to claim 1, wherein said query messages each include a query type indicator, step (a) involving selecting all query messages that have a predetermined query type indicator. 
     
     
       3. A method according to claim 1, wherein said query messages each include a query type indicator, step (a) involving selecting only those queries that are both addressed to said service function node and are of one or more predetermined types. 
     
     
       4. A method according to claim 1, wherein said service function node has only virtual presence as an address for said query messages. 
     
     
       5. A method according to claim 1, wherein step (b) involves looking up said response data in a database, said database being shared with said service function node. 
     
     
       6. A method according to claim 1, wherein step (a) is carried out on messages en route for said service function node via a signalling transfer point of said signalling network, said response messages being forwarded in step (d) to said signalling transfer point and the latter serving to redirect said response messages back to said querying entity. 
     
     
       7. A method according to claim 1, wherein said selected query messages relate to local number portability and each contain a called party number, step (b) involving, where said called party number is a ported number, providing as said response data a location routing number indicative of a switching point from which the called party currently depends. 
     
     
       8. A method according to claim 1, wherein the passing of said messages over said at least one link of the signalling network is effected in accordance with a link-level protocol having state, steps (a) and (d) being effected without affecting the current state of the link-level protocol on the link concerned. 
     
     
       9. A method according to claim 1, wherein the passing of said messages over said at least one link of the signalling network is effected in accordance with a link-level protocol having state, steps (a) and (d) being effected by setting up independent link-level protocol exchanges with each end of the link concerned whereby in step (a) said query messages are intercepted by reception from one end of the link in accordance with the link-level protocol operated therewith, and in step (d) the response messages are forwarded by transmission to the other end of the link in accordance with the link-level protocol operated therewith. 
     
     
       10. Apparatus for relieving the loading of a service function node to which query messages are addressed over a telecommunications signalling network from a querying entity, said query messages each including source and destination data and giving rise to corresponding response messages returned to said querying entity over said signalling network; said apparatus comprising: means for intercepting messages on at least one link of said signalling network and selecting from the intercepted messages at least certain of said query messages addressed to the service function node;   means for generating, for each selected query message, appropriate response data;   means for replacing each said selected query message with a response message including said response data, the response message having its destination data set to the source data of the corresponding query message; and   means for forwarding on said response messages over the signalling network, said response messages being forwarded in a direction corresponding to that in which said query messages were traveling when intercepted in step (a).   
     
     
       11. A telecommunications system including a signalling network with signalling transfer points, a service function node connected to said signalling network for receiving query messages and returning corresponding response messages, and a querying entity connected to said signalling network for addressing query messages to said service function node and receiving back therefrom said corresponding response messages, each said query message including source and destination data; said system further comprising: means connected into a link of said signalling system to intercept messages carried by that link, said link being one carrying query messages en route for said service function node via a said signalling transfer point of said signalling network;   means for selecting from the intercepted messages at least certain of said query messages addressed to the service function node;   means operative for each selected query message, to generate appropriate response data;   means for replacing each said selected query message with a response message including said response data, the response message having its destination data set to the source data of the corresponding query message; and   means for forwarding on said response messages over the signalling network in a direction corresponding to that in which said query messages were traveling when intercepted in step (a), via said signalling transfer point.